When I go to my shop page and I have the filters on the left-hand side with the price filter slider appearing with no issues. When I click on any sub-category in the shop, the price sliders becomes two fields (min and max price) rather than a slider.
Unfortunately default WooCommerce Price filter doesn’t work after AJAX page reloading. That is why we have developed our own “Basel Price filter”. So you can use our widget or you need to disable ajax in Theme Settings -> Shop -> AJAX shop